1. Field of the Invention
The present invention relates to an automotive vehicle air conditioning system, and more particularly to an airflow distribution controlling device for an automotive vehicle air conditioning system having a distributor duct branching off into two outlet ducts.
2. Description of Related Art
In an automotive air conditioning system having a distributor duct branching off into two outlet ducts for delivering air toward driver's and front passenger's seats, respectively, there is a requirement of delivering air through the two outlet ducts in various proportions. To deliver air in required proportions, a control door, which is provided at a junction for the two outlet ducts, closes partly or fully either one of the two outlet ducts when the other outlet duct is required to blow off a high proportion of air. Such an automotive vehicle air conditioning system is known from Japanese Unexamined Utility Model Publication No. 61-110,416 entitled "Ventilator", laid open Jul. 12, 1986.
The provision of a control door disposed at the junction for delivering air in required proportions to the outlet ducts causes an increase of fluid friction of air against the control door, resulting in not only increasingly loading a motor of a fan but also decreasing the amount of air delivered into a vehicle compartment. Such an increase of fluid friction of air also causes an increase of air pressure against the control door, resulting in an increased force of operating the control door to change the distribution of air into the two outlet ducts.